Non-expendible gun for use in jet perforating



P 4, 1956 w. G. SWEETMAN 2,761,383

NON-EXPENDIBLE GUN FOR USE IN JET PERFORATING Filed Aug. 8, 1951 2Sheets-Sheet l W/AZ/AM 6. SWEET/MAN INVENTOR.

BY w k ATTC/TA... Y.

Sept- 4, 1956 w. G. SWEETMAN 2,761,383

NON-EXPENDIBLE GUN FOR USE IN JET PERFORATING Filed Aug. 8, 1951 2Sheets-Sheet 2 W/LL/AM 6. SWEET/WAN INVENTOR.

BY a;

ATTORNEY Patented Sept. 4, 1956 NON-EXPENDIBLE GUN FOR USE IN JETPERFORATING William G. SweetmamHouston, Tex.

Application August 8, 1951, Serial No. 240,935

3 Claims. (Cl. 102-20) This invention relates to carriers, or so-calledguns, employed in the art of perforating wells, which are adapted tosupport explosive perforating units of the hollowed type, commonlyreferred to in the art as jet charges, the art itself being usuallyknown as jet perforating.

Various types of such carriers of guns have heretofore been designedwhich fall into two general classes, to wit: expendible andnon-expendible types. The expendible types are normally constructed ofshatterable materials, both metallic and non-metallic, which aredesigned to be I disintegrated as completely as possible by theexplosion of the charges. The non-expendible type is normallyconstructed in the form of a massive steel body provided with sockets orreceptacles in which the charges are seated, and which, after firing ofthe charges, is withdrawn from the well for reloading and re-use. Thepresent invention is directed particularly to the non-expendible type ofcarrier, which is advantageous for use in many instances where the useof expendible type carriers is found to be undesirable or unadapted forone reason or another.

Non-expendible guns are necessarily relatively expensive to construct,since they must normally be made of tough alloy steels and of massiveconstruction in order to withstand the destructive forces resulting fromthe firing of the high explosive perforating charges. Moreover, thecharge sockets and seating surfaces for the charges, and the variousopenings and sealing closures therefor, must ordinarily be machined tovery close tolerances and these are particularly subject to thebattering and destructive action of the forces released by the explosionof the charges. Present types of non-expendible guns, therefore,ordinarily require remachining, often after each run or, at best, afteronly a very few runs, and this is not only expensive but necessarilysharply limits the total number of times the gun may be re-used.

Accordingly, the principal object of the present invention is to providean improved non-expendible type of carrier or gun for jet perforatingwhich is relatively unaflected by the force of the exploding charges andwhich, therefore, is capable of re-use a much larger number or" timesthan the more conventional forms of non-expendible guns.

A more specific object is to provide a gun having a cylindrical body ofrelatively massive construction provided with a series of longitudinallyspaced passages extending transversely entirely through the body, thepassages being angularly oriented with respect to each other about thelongitudinal axis of the body; the opposite outer ends of each passagebeing shaped to form receptacles or seating sockets for individualperforating units, the sockets in each passage being in opencommunication with each other at their inner ends.

A further object is to provide a gun having the socket arrangementmentioned in which for each run only one charge is mounted in one socketof each pair, the other socket of each pair forming a vent for relief ofpressure resulting from the firing of the charge.

A further object is to provide a gun having the socket arrangementmentioned in which the charges are selectively arranged in the socketsin such manner as to provide clockwise orientation of the series ofcharges along the gun body.

Other and more specific objects and advantages of this invention willbecome apparent from the following detailed description when read inconjunction with the accompanying drawings which illustrate a usefulembodiment in accordance with this invention.

In the drawings:

Fig. l is an elevational view of the complete gun having some of theparts thereof broken away for purposes of illustration;

Fig. 2 is a diagrammatic representation of a planar development of aportion of the gun surface to illustrate the spatial relationships ofthe charge sockets;

Fig. 3 is a horizontal cross-sectional view taken along line 3-3 of Fig.1;

Fig. 4 is a longitudinal sectional view of one of the charge-seatingpassages of the gun;

Fig. 5 is a transverse sectional view taken along line 55 of Fig. 4; and

Fig. 6 is a longitudinal sectional view taken along line 66 of Fig. 4.

As shown in the drawings, the gun comprises an elongated generallycylindrical body 10, which is normally constructed from a solid billetof a suitable alloy steel. Body 10 is provided at its upper end with aninternally threaded socket 11 and at its lower end with an externallythreaded pin member 12. An axial bore 13 extends entirely through thebody, its upper end communicating with the bottom of socket 11 and itslower end opening through the outer end of pin member 12.

Extending entirely through body 10 at right angles to its longitudinalaxis are a plurality of longitudinally spaced passages 14 which areangularly oriented with respect to each other about the longitudinalaxis of the body.. As shown in detail in Figs. 4, 5 and 6, the outerends of each passage 14 are machined or otherwise shaped to formoutwardly flaring generally conical sockets 15, the taper of each socketextending outwardly from points immediately adjacent bore 13 and on therespective opposite sides thereof, thereby forming an internal shoulder16 at the inner end of each socket and defining a narrow annular wall 17between the shoulders 16 which extends circumferentially of passage 14.At the inner end of each socket, at the upper and lower sides thereof,short notches 18 are cut radially through the wall of the socket intocommunication with bore 13, each notch extending into bore 13 at anangle to the wall of the socket to thereby provide a sloping wall 19extending between the wall of the socket and bore 13. Each socket isprovided adjacent its outer end, and on opposite sides thereof with apair of holes 2020 which extend from the wall of the socket through body10 to the exterior thereof. It will be seen that the sockets 15 in eachpassage are substantially identical in form and symmetrical with respectto the longitudinal axis of the body.

Mounted in one of the sockets 15 of each of the passages 14 is ahollowed high explosive perforating unit, designated generally by thenumeral 21. Perforating units 21 are of the self-contained hermeticallysealed type, described in detail in my co-pending application Serial No.163,146, filed May 20, 1950, now Patent No. 2,629,325, dated February24, 1953. As shown in Fig. 3, perforating unit 21 comprises a glasscasing 22 of generally ovoid or egg-shape, the larger end being directedtoward the outer end of the socket. Casing 22 is provided near itssmaller end with an external annular shoulder 23 adapted to be engagedby shoulder 16 when the unit is inserted in socket 15 to thereby form aninternal stop for the unit and to position the perforating unit with itsouter end substantially flush or slightly inside the outer end of socket15. A charge of high explosive 24 is completely enclosed within-casing22 and is provided at its outer end with a generally conical hollow 25facing toward the outer end of socket 15, and with a thin metallic liner26 conforming in shape to, and seated Within, hollow 25. The perforatingunit is held in place in socket by means of a wire keeper 27 whichpasses transversely over the outer end of casing 22 and has its oppositeends threaded through holes 20 on opposite sides thereof and crimpedover the outer edges of holes 20, or otherwise suitably fastened, tohold the perforating unit in place in socket 15 against shoulder 16.

The inner end of casing 22, adjacent the inner end of charge 24, isprovided with a notch 28 for the reception of a suitable detonatingelement 29, such as the well known Primacord, which passes transverselyacross the inner end of casing 22 and through notch 18 into bore 13 onopposite sides of socket 15. The sloping surfaces provided by walls 19of notches 18 allows the detonating cord to enter bore 13 withoutforming sharp bends or creases therein which would otherwise interferewith the effective transmission of detonating shock along the detonatingcord to the series of perforating units over which the detonating cordis trained.

Detonating cord 28 is threaded through bore 13 and passes successivelyover the inner ends of each of the series of perforating units mountedin body 10. The lower end of the detonating cord is suitably anchored tothe lower end of threaded pin 12 which is enclosed by a threaded cap 30.The upper endvof the detonating cord extends into socket 11 and passesinto the bore 31 of a firing head 32 which is threadedly connected intosocket 11. Firing head 32 is of a generally conventional form, thedetails of which do not form a part of this invention. As is wellunderstood in the well-perforating art, firing head 32 will contain anelectrically fired initiator which is connected to a suitable source ofelectric current through a conducting cable 33 which extends to thesurface and is connected to firing head 32 by means of a conventionalconnector or so-called rope-socket 34, by which electric current istransmitted from the cable to the initiator, the cable being also usedto lower the gun into a well.

When a hollowed explosive charge, such as that employed in a perforatingunit 22, is fired, it is characteristic of such charges that a portionof the explosive forces will be concentrated into a narrow perforatingjet or column which will be projected from the hollowed end of thecharge along its longitudinal axis. At the same time the remainder ofthe explosive force generated by detonation of the charge will dischargein random manner in all directions about the charge and unless suitablycontrolled or directed, will tend to produce severe battering and otherdestructive action on the surrounding parts of the gun. By mounting onlya single perforating unit in only one of the sockets of each pair formedin each passage 14, it will be seen that the unoccupied socket will forman outwardly flaring vent of relatively large diameter through which therandom explosive forces may be channeled and directed to the exterior ofthe gun. As a result of so confining and directing the random forces,their normally destructive action on the adjacent parts of the gun bodywill be very largely obviated so that the sockets will remainsubstantially undamaged and the gun may be reloaded and re-used a verylarge number of times.

Ordinarily, after firing one series of charges, the next series will beloaded in the sockets in the opposite ends of the passages 14 so thatsuccessive firings will take place in alternate ends of the passages.This further tends to protect the gun and of itself doubles the numberof times the gun may be run.

A very important factor in greatly lengthening the life of the gun isprovided by means of a novel loading arrangement in which the shots ofeach series are mounted in selected ones of the sockets in such a mannerthat the shots will be oriented with respect to each other in theclockwise direction about the longitudinal axis of the gun.

Fig. 2 illustrates schematically the desirable orientation arrangementfor a series of four passages corresponding to a one-foot length of thegun, it being assumed for purposes of illustration that passageways 14are longitudinally spaced on three-inch centers and are oriented at withrespect to each other. One end of each passageway is designated by theletter F and the opposite end by the letter R, the sub-scripts 1, 2, 3and 4 designating the corresponding ends of the successively lowerpassages. In the development shown in the lower diagram of Fig. 2, theends of all four passagestar-e shown in their relative spatialpositions. It will be seen that viewed in the clockwise direction aroundthe gun, ends F1, F2, F3 and F4 of the successive passages 14 will bespaced from each other by the distance a which is substantially greaterthan the distance b which is the distance between an end P of onepassage and an end R of the next lower passage, considered in theanti-clockwise direction. Accordingly, by inserting the perforatingunits of a series of shots only in ends F1, F2, F3 and F4, a maximumthickness of metal will be provided between each pair of shots therebygreatly 1ncreasing the degree of protection of each socket and theadjacent parts of the body from the effect of explosion of the charge inthe next succeeding socket in the series. The next series of shots maythen be installed only in the ends R1, R2, R3 and R4, again in theclockwise direction and the same maximum spacing between shots will beprovided.

From the foregoing it will be seen that a gun body is provided whichrequires a minimum amount of machirung, since no carefully machinedsockets or charge seating surfaces are required, and by reason of theemployment of hermetically sealed, self-contained perforating units, theneed for carefully machined sealing surfaces and closures for the gunopenings is eliminated. The cost of the gun is thereby greatly reduced.Moreover, the constructlon and loading arrangement described assuresmaximum protection of the parts of the gun against the normallydestructive action of the explosive forces resulting from detonation ofthe perforating units thereby permitting re-use of the gun a much largernumber of times than has heretofore been possible with the moreconventional designs of non-expendible perforating guns.

It will be understood that various changes and modifications may be madein the details of the illustrative embodiment within the scope of theappended claims without departing from the spirit of this invention.

What I claim and desire to secure by Letters Patent:

1. In a perforating gun for use in jet perforating, a non-expendiblecarrier, comprising, an elongated cylindrical body of relatively massivemetallic construction, an axial bore relatively small in cross-sectionextending through said body, a plurality of longitudinally spacedpassages extending diametrically through said body intersecting saidbore and angularly oriented with respect to each other about thelongitudinal axis of said body, each of said passages including a pairof oppositely directed generally conical sockets each flaring outwardlyat a substantial angle, the taper of each socket extending outwardlyfrom points immediately adjacent said axial bore, said sockets beingsubstantially identical in shape and symmetrical with respect to saidlongitudinal axis and in open communication with each other throughtheir inner ends, a self-contained hermetically sealed hollowed highexplosive perforating unit including a frangible case mounted in one ofthe sockets in each passage with its hollowed end directed outwardly ofsaid one socket and with its opposite end extending within the socket atthe opposite side of said passage, an internal annular shoulder formedat the inner end of each socket adjacent said bore adapted to engage anenlarged portion of the unit to form a supporting stop for the unit,means for retaining each unit in engagement with its respectivesupporting stop, a cord-type detonating element extending through saidbore into successive detonating relation with the inner ends of saidseries of units, and means connected to said body for firing saiddetonating element.

2. A non-expendible perforating gun for use in jet perforating,comprising, an elongated cylindrical body of relatively massive metallicconstruction, an axial bore relatively small in cross-section extendingthrough said body, a plurality of longitudinally spaced passagesextending diametrically through said body intersecting said bore andangularly oriented with respect to each other about the longitudinalaxis of said body, each of said passages including a pair of oppositelydirected generally conical sockets each flaring outwardly at asubstantial angle, the taper of each socket extending outwardly frompoints immediately adjacent said axial bore, said sockets beingsubstantially identical in shape and symmetrical with respect to saidlongitudinal axis and in open communication with each other throughtheir inner ends, a self-contained hermetically sealed hollowed highexplosive perforating unit including a frangible case mounted in one ofthe sockets in each passage with its hollowed end directed outwardly ofsaid one socket and with its opposite end extending within the socket atthe opposite side of said passage, the sockets in which said units aremounted being selected to provide clockwise orientation of the series ofunits along said body, means for retaining each unit in its socket, acord-type detonating element extending through said bore into successivedetonating relation with the inner ends of said series of units, andmeans connected to said body for firing said detonating element.

3. In a non-expendible perforating gun according to claim 2, whereinsaid means for retaining each charge in its socket comprises a reducedpassage formed by the conical inner end of the socket adjacent said boreadapted to engage an enlarged portion of the unit to form a supportingstop for said unit, a pair of holes in said body on opposite sides ofsaid socket extending from the exterior of said body to the interior ofsaid socket adjacent its outer end, and a keeper wire extendingtransversely over the outer end of said unit and having its oppositeends anchored in said holes.

References Cited in the file of this patent UNITED STATES PATENTS1,582,184 Mims Apr. 27, 1926 2,139,104 Wells Dec. 6, 1938 2,391,932Turechek Jan. 1, 1946 2,402,153 Elliott June 19, 1946 2,494,256 Muskatet a1. Jan. 10, 1950 2,506,836 Kaltenberger May 9, 1950 r 2,507,230Stinnett May 9, 1950 FOREIGN PATENTS 962,308 France Dec. 5, 1949 OTHERREFERENCES Article by R. H. McLemore entitled Casing Perforating withShaped Explosive Charges in December 28, 1946, issue of The Oil and GasJournal.

